Film optical image bar code reader

1. A bar code reader for reading an optical bar code image having parallel rows of clock and data elements extending longitudinally along the length of a filmstrip, the row of clock elements having at least one longitudinally extending edge transition, the reader comprising: a film path; an illuminant source; a linear, pixel-by-pixel light sensor array for detecting illuminant from said source passing through said filmstrip in a region encompassing said bar code image; a scanning aperture defining a window of exposure of said illuminant source through said bar code onto said light sensor array; a light sensor array for detecting illuminant from said source passing through said film in a region encompassing said bar code image; and a data processing controller responsive to output information from the light sensor array from within said bar code exposure window for laterally locating said longitudinal edge transition of an element in the row of clock elements and for determining binary values of the clock and data elements from the sensor array output information at predetermined spaced locations relative to the located edge transition of the element in the row of clock elements.

2. The reader of claim 1 wherein said located clock edge transition is a line of transition between said rows of clock and data elements.

3. The reader of claim 1 wherein said located clock edge transition is a line of transition remote from said row of data elements.

4. The reader of claim 1 wherein said located clock edge transition is a line of transition adjacent a central image area on the filmstrip.

5. The reader of claim 1 wherein said scanning aperture includes a mask portion restricting said window of exposure to a region inward of an edge of said filmstrip.

6. The reader of claim 1 wherein said scanning aperture includes a mask portion restricting transmission to said light sensor array of light from said illuminant to a region of said filmstrip which is inward of an edge of the filmstrip.

7. A method in a film scanner of adaptively locating and reading a bar code image imprinted adjacent an edge of a filmstrip, the bar code image having abutting rows of clock and data elements said clock elements having a line of edge transition extending longitudinally along the filmstrip, the film scanner having an illuminant source and a linear light sensor array for detecting light from the illuminant source transmitted through said bar code image, the method comprising: passing said filmstrip bar code image over a bar code scanning aperture; transmitting said illuminant light through said bar code image and scanning aperture toward said light sensor array thereby defining a window of exposure of said illuminant light onto said linear light sensor array; processing output information from said light sensor array to determine lateral location of said clock element line of edge transition; establishing clock and data element detection windows at predetermined spaced locations from said located longitudinally extending edge transition of a clock element; and determining binary values of the clock and data elements in the bar code image from light sensor array output information in said clock and data element detection windows.

8. The method of claim 7 wherein said located edge transition of a clock element is a line of transition between said clock and data elements and said clock and data element detection windows are on opposite sides of said line of transition between said clock and data elements.

9. The method of claim 7 wherein said located edge transition of a clock element is a clock edge transition remote from said data elements. and adjacent to image frame regions on said filmstrip.

10. The method of claim 7 wherein said located edge transition of a clock element is a clock edge transition adjacent to image frame regions on said filmstrip.

11. A method in a film scanner of adaptively locating and reading a bar code image imprinted adjacent an edge of a filmstrip, the bar code image having abutting rows of clock and data elements said clock elements having a line of edge transition extending longitudinally along the filmstrip and said bar code includes an entry element comprising a clock and data element of high density, the film scanner having an illuminant source and a linear light sensor array for detecting light from the illumninant source transmitted through said bar code image, the method comprising: passing said filmstrip bar code image over a bar code scanning aperture; transmitting said illuminant light through said bar code image and scanning aperture toward said light sensor array thereby defining a window of exposure of said illuminant light onto said linear light sensor array; processing output information from said light sensor array to determine lateral location of said clock element line of edge transition; establishing clock and data element detection windows at predetermined spaced locations from said located longitudinally extending edge transition of a clock element, defining lateral beginning and end points of said aperture window by an open gate line scan and thereafter processing said output information from within said defined beginning and end points of the aperture window to locate said edge transition of a clock element; and; determining binary values of the clock and data elements in the bar code image from light sensor array output information in said clock and data element detection windows.

12. The method of claim 11 further including moving said filmstrip through said defined aperture window; performing successive line scan operations as the filmstrip is moved; and locating a leading edge of said entry element from output information from said light sensor from within said defined aperture window.

13. The method of claim 12 further including moving said filmstrip a predetermined distance from said located leading edge to align a predefined portion of the barcode with said defined aperture window and wherein said processing of output information comprises performing at least one line scan on said predefined portion of the barcode to produce a profile of the barcode in said output information and said processing of output information further includes locating a maximum delta change of transition value to locate said longitudinally extending edge transition of a clock element.

14. The method of claim 13 in which said predefined portion of the barcode is a position at which the clock element has a maximum density value and the data element has a minimum density value and said located delta change of transition value corresponds to a line of transition between said clock and data elements.

15. The method of claim 13 wherein said predefined portion of the barcode is a position at which the clock and data elements both have maximum density value and said located delta change of transition value corresponds to a clock edge of the clock element.

16. The method of claim 15 wherein said clock and data element detection windows are established at predetermined offset locations spaced from said located clock edge of the clock element.

17. The method of claim 11 further including moving said filmstrip through said defined aperture window, performing successive line scan operations as the filmstrip is moved; said processing of output information from said light sensor array is performed on each successive line scan to locate a clock edge of said clock element.

18. The method of claim 17 wherein said clock and data element detection windows are established at predetermined offset location spaced from the located clock edge of the clock element.